Zephyr API Documentation 4.0.0-rc2
A Scalable Open Source RTOS
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linker-devnull.h
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1/*
2 * Copyright (c) 2023 Nordic Semiconductor ASA
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7/*
8 * DESCRIPTION
9 * Platform independent set of macros for creating a memory segment for
10 * aggregating data that shall be kept in the elf file but not in the binary.
11 */
12
13#ifndef ZEPHYR_INCLUDE_LINKER_LINKER_DEVNULL_H_
14
15#if defined(CONFIG_LINKER_DEVNULL_MEMORY)
16
17#if defined(CONFIG_XIP)
18#if (!defined(ROM_ADDR) && !defined(ROM_BASE)) || !defined(ROM_SIZE)
19#error "ROM_SIZE, ROM_ADDR or ROM_BASE not defined"
20#endif
21#endif /* CONFIG_XIP */
22
23#if (!defined(RAM_ADDR) && !defined(RAM_BASE)) || !defined(RAM_SIZE)
24#error "RAM_SIZE, RAM_ADDR or RAM_BASE not defined"
25#endif
26
27#if defined(CONFIG_XIP) && !defined(ROM_ADDR)
28#define ROM_ADDR ROM_BASE
29#endif
30
31#if !defined(RAM_ADDR)
32#define RAM_ADDR RAM_BASE
33#endif
34
35#define ROM_END_ADDR (ROM_ADDR + ROM_SIZE)
36#define DEVNULL_SIZE CONFIG_LINKER_DEVNULL_MEMORY_SIZE
37#define ROM_DEVNULL_END_ADDR (ROM_END_ADDR + DEVNULL_SIZE)
38#define MAX_ADDR UINT32_MAX
39
40/* Determine where to put the devnull region. It should be adjacent to the ROM
41 * region. If ROM starts after RAM or the distance between ROM and RAM is big
42 * enough to fit the devnull region then devnull region is placed just after
43 * the ROM region. If it cannot be done then the devnull region is placed before
44 * the ROM region. It is possible that the devnull region cannot be placed
45 * adjacent to the ROM (e.g. ROM starts at 0 and RAM follows ROM). In that
46 * case compilation fails and the devnull region is not supported in that
47 * configuration.
48 */
49#if !defined(CONFIG_XIP)
50
51#if RAM_ADDR >= DEVNULL_SIZE
52#define DEVNULL_ADDR (RAM_ADDR - DEVNULL_SIZE)
53#else
54#define DEVNULL_ADDR (RAM_ADDR + RAM_SIZE)
55#endif
56
57#else /* CONFIG_XIP */
58
59#if ((ROM_ADDR > RAM_ADDR) && ((MAX_ADDR - ROM_END_ADDR) >= DEVNULL_SIZE)) || \
60 ((ROM_END_ADDR + DEVNULL_SIZE) <= RAM_ADDR)
61#define DEVNULL_ADDR ROM_END_ADDR
62#elif ROM_ADDR > DEVNULL_SIZE
63#define DEVNULL_ADDR (ROM_ADDR - DEVNULL_SIZE)
64#else
65#error "Cannot place devnull segment adjacent to ROM region."
66#endif
67
68#endif /* CONFIG_XIP */
69
70#define DEVNULL_REGION DEVNULL_ROM
71
72#endif /* CONFIG_LINKER_DEVNULL_MEMORY */
73
74#endif /* ZEPHYR_INCLUDE_LINKER_LINKER_DEVNULL_H_ */